It was a motherboard. A Lenovo IS7XM Rev 1.0.
Standard off-the-shelf power supplies and cases may require adapters to work with this proprietary board: Power Supply : Uses a non-standard 14-pin main ATX power connector (instead of the standard 24-pin). A 24-pin to 14-pin adapter is typically needed for aftermarket PSUs. USB Headers : Features a proprietary 11-pin USB header rather than the standard 9-pin. Front Panel lenovo is7xm rev 1.0 motherboard manual
The front panel pins (Power SW, Reset, LED) are often in a proprietary block that may not match standard case cables without custom wiring. It was a motherboard
, primarily designed for Lenovo ThinkCentre business desktops like the M82, M92, and M92p Technical Specifications Processor Support and M92p Technical Specifications Processor Support